Why doesn't php5.6 see memcached?

Question

PHP

PHP 7.0 was installed on the server. For the needs of the project, we also installed php 5.6. When trying to install the memcahed module, it only appears in version 7.0. When you enter through the ubuntu command line, it says that php 7.0 is running and memcahed is connected. Running phpinfo() on the site shows "PHP Version 5.6.30" and no memcahed module. How to make memcahed work on php 5.6